Ignition system



June 5, 1945. w |N| OR 2,377,793

IGNITION SYSTEM Filed Deb. 23, 1943 Inventor: P William I. Linlor HisAttorney.

iatented June 5, 1945 omrrn 1 STATES" grimy IGNITIDN SYSTEM William I.Linlor, Schenectady, N. W assignor to General Electric Company, acorporation off New York I Application December 23, 1943, Serial No.515.3413

11 Claims.

improved ignition system utilizing a magneto having a tertiary windingand an auxiliary circuit breaker for minimizing overlap in the system. v

Further objects and advantages of my invention will become apparent andmy invention will be better understood from the following descriptionreferring to the accompanying drawing, and the features of novelty whichcharacterize'my invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

The drawing schematically illustrates an ignition system provided withan embodiment of my invention.

Referring to the drawing, I have shown an ignition system provided witha plurality of spark .plugs it having grounded electrodes ll and cen-.-.tral discharge electrodes l2 connected to a plurality of distributorelectrodes B3; The distributor is. arranged todistribute ignitioncurrent sequentially to the spark plugs through a dis tributing elementit which is connected to one terminal of a magneto secondary winding i5.This magneto secondary Winding 115 forms part of a magneto which isadapted to supply the energizing current to the ignition system. In thistype system, operation at high speeds tends to make the magneto overlap.This overlap" is the failure of a. magneto to fire at high speed becausethe operation of the conventional breaker interferes with electricaltransients in the system; that is, the breaker across the primarywinding of the magneto closes before complete ,decay of the electricaloscillations which were set up by the opening of the breaker. In myimproved ignition system, I provide against this condition and minimizethe possibility of. its 00- currence by dissipating the energy in thesystem prior to the reclosing of the breaker contacts whichare connectedacross the magneto primary winding. The magneto is provided with arotatable member IB adapted to be driven at a predetermined speedrelative to the-engine crank shaft through a mechanical connection by ashaft H which is also; arranged to drive the. distributing element ll ofthe distributor. A stationary which the windings oi the magneto areinductively arranged. A primary winding id is arranged about the coreiii and a voltage is adapted to be induced in the winding it byelectromagnetic action when the rotatable member it is operated by theengine. This primary winding it is connected across a set of breakercontacts 2t and ill which are adapted to be operated by a follower 22and a cam 23 operable by the shaft it and responsive to the speed of theengine to which the ignition of thesystem is supplied. A condenser it isconnected across the breaker contacts at and M to minimize burning ofthe contacts. The magneto, in addition, is provided with a tertiarywinding 25 arranged on the core member it and this winding is connectedacross an aumliary circuit breaker formedby a breaker contact it and thebreaker contact 2 i. In the arrangement shown, this auxiliary breaker isalso adapted to be operated by the followerv 2i and the cam 23 of themain breaker.

Obviously, a separate breaker and cam could be provided if desired. Inthe arrangement the circuit of the magneto primary winding Elli is keptclosed until the current induced therein by the rotation of therotatable member Mi reaches substantially its highest value, at whichtime the cam it raises the follower t2 and opens the primary windingcircuit by breaking the circuit between the contacts 2i and 22. Thiscauses a rapid decay of the current in the primary winding and induces arelatively high voltage in the magneto secondary winding it. This is theposition of the elements shown in the drawing. At this instant, thedistributing element M is opposite one of the distributor electrodes l3,and a spark discharges across a gap therebetween and supplies the highpotential impulse from the secondary winding it to one of the spark plugdischarge electrodes it, thereby causing an electrical breakdown of thatspark plug. After a spark plug has fired, it is desirable that theenergy in the system should be dissipated as rapidly as possible toprovide for sequentially repea'ting theabove events. In order to dothiswithout "overlap, the cam 27? is adapted to raise the follower 22further than the amount required to open the circuit between the breakercontacts 20 and 2! and to raise the grounded breaker contact 2! until itcloses the circuit through the.

. core of magnetic material [8 is provided about 55 V the magneto tothis short-circuited winding. In

order to dissipate this energy, the tertiary winding preferably shouldhave a resistance in the range of 50 to 100 ohms, and the closing ofthese contacts should occur very shortly after the impulse for thebreakdown of the spark plug and might be in the order of two or threeelectrical degrees of angle of rotation of the distributing element [4.This also minimizes arcing of the distributor contacts as the energy israpidly dissipated in the tertiary winding rather than in the arebetween the spark plug electrodes and between the distributor electrodesI3 and the dis- .tributing element It. In, order to permit the properbuild up of flux in the core and primary winding for the sequentialoperation of the system, the circuit of the tertiary winding 25 isopened by the tertiary winding circuit breaker contacts 26 and 2| whenthe cam. 23 is rotated. This opening of the tertiary winding circuit, ismade to occur a short interval before each closing of the primarywinding circuit breaker, and this interval should be about fiveelectrical degrees of distributor angle of rotation. If the cam 23rotates and opens the tertiary winding circuit, the follower 22 permitsthe breaker contact 2| to reengage the breaker contact 20 a shortinterval of time after the opening of the tertiary winding circuit withthe breaker contact 28, thereby sequentially closing the primary windingcircuit. This closing of the primary winding circuit should occurperiodically at substantially the attainment of maximum magnetic flux inthe core I8, that is, at substantially the time when the pole pieces oithe rotatable member l8 leave the edge of one of the faces of the polesof the core l8. In this manner, the magneto rotatable member [6sequentially induces a current in the magneto primary winding l9 whichsequentially produces a voltage in the magneto secondary winding I whichin turn is sequentially distributed to the various spark plugs of thesystem, and overlap, as well as arcing and burning of the magnetoelectrodes and distributing elements is prevented or minimized by theoperation of the tertiary winding circuit.

While I have illustrated and described a particular embodiment of myinvention, modifications thereof will occur to those skilled in the art.I desire it to be understood, therefore, that my invention is not to belimited to the particular arrangement disclosed, and I intend in theappended claims to cover all modifications which do not depart from thespirit and scope of my invention.

What I claim as new and desire to secure by etters Patent of the UnitedStates is:

1. An ignition system including a magneto having a magnetic circuit witha core of magnetic material, a primary winding on said core, a secondarywinding on said core, a tertiary winding on said core, means forsequentially opening the circuit of said primary winding for inducing avoltage in said secondary winding for distribution to spark plugs, and,means for sequentially closing the circuit of said tertiary winding a'short interval after each electrical impulse for breakdown oi the sparkplugs for dissipating the electromagnetic .energy of said magneto insaid tertiary winding.-

2. An ignition system including a magneto having amagnetic circuit witha core o! magnetic material, a primary winding on said core, a seemarywinding for inducing a voltage in said secondary winding fordistribution to said spark plugs, and means for sequentially closing thecircuit of said tertiary winding a short interval after each electricalbreakdown of said spark plugs for dissipating the electromagnetic energyof said magneto in said tertiary winding.

3. An ignition system including a magneto having a core, a primarywinding on said core, a secondary winding on said core, a tertiarywinding on said core. a distributor arranged to distribute ignitioncurrent sequentially to spark plugs from said secondary winding, meansfor sequentially opening the circuit of said primary winding onattainment of substantially maximum induced electric current in saidprimary winding and for periodically sequentially closing the circuit ofsaid primary winding after a predetermined opmaterial, a primary windingon said core, a secondary winding on said core,'a tertiary winding onsaid core, a distributor arranged to distribute ignition currentsequentially to spark plugs from said secondary winding, means forsequentially opening the circuit of said primary winding on attainmentof substantially maximum induced electric current in said primarywinding for producing a voltage in said secondary winding fordistribution to the spark plugs and for periodically sequentiallyclosing thecircuit of said primary winding after a predeterminedoperation of said system, and means for sequentially closing the circuitof said tertiary winding a short interval after each opening of saidprimary winding circuit breakerv and after electrical breakdown of thespark plugs for dissipating the electromagnetic energy of said magnetoin said tertiary winding.

5. An ignition system including a magneto having a magnetic circuit witha core of magnetic material, a primary winding on said core. a secondarywinding on said core, a tertiary winding on said core, a plurality ofspark plugs, a distributor arranged to distribute ignition currentsequentially to said'spark plugs from said secondary winding. means forsequentially opening the circuit of said primary winding on attainmentof substantially maximum induced. electric current in said primarywinding for producing a voltage in said secondary winding fordistribution to said spark plugs and for periodically sequentiallyclosing the circuit of said primary winding after a predeterminedoperation of said system,

i and means for sequentially closing the circuit of said tertiarywinding a short interval attereach opening of said primary windingcircuit breaker and after electrical breakdown of said spark plugs fordissipating the electromagnetic energy of said magneto in said tertiarywinding and for opening the circuit of said tertiary winding prior tothe ondary winding on said core, a tertiary winding 1 on said core,aplurality oi spark plugs, means.

closing of said primary winding circuit.

6. An ignition system including amagneto having a magnetic circuit witha core or magnetic material, a primary winding on said core, a secondarywinding on said core, a tertiary winding on said core. a' plurality oispark plugs, a distributor arranged to distribute ignition currentsequentially to, said spark plugs from said secondary winding, means forsequentially opening the circuit of said primary winding on attainmentof substantially maximum induced electric current in said primarywinding for producing a voltage in said secondary winding fordistribution to said spark plugs and for periodically sequentiallyclosing the circuit; of said primary winding after a predeterminedoperation of said system, and means for sequentially closing the circuitof said tertiary winding a short interval after each opening of saidprimary winding circuit breaker and after electrical breakdown of saidspark plugs for dissipating the electromagnetic energy of said magnetoin said tertiary winding. I

'1. An ignition system including a magneto having a magnetic circuitwith a core of magnetic material, aprimary winding on said core, asecondary winding on said core, a tertiary winding on said core, aplurality of spark plugs, a distributor arranged to distribute ignitioncurrent sequentially to said spark plugs from said secondary winding,means including a primary winding circuit breaker operable forsequentially opening the circuit of said primary winding on attainmentof substantially maximum induced electric current in said primarywinding for producing a voltage in said secondary winding fordistribution to said spark plugs andfor periodically sequentiallyclosing the circuit of said primary winding after a predeterminedoperation of said system, and means including a tertiary winding circuitbreaker operable for sequentially closing the circuit 01- said tertiarywinding a short interval after each opening of said primary windingcircuit breaker and after electrical breakdown of said spark plugs fordissipating the electromagnetic energy or said magneto in said tertiarywinding.

8. An ignition system including a magneto having a magnetic circuit witha core of magnetic material, a primary winding on said core, a secondarywinding on said 'core, a tertiary winding on said core, a plurality ofspark plugs, a distributor arranged to distribute ignition currentsequentially to said spark plugs from said secondary winding, means forsequentially opening the circuit 01 said primary winding on attainmentof substantially maximum induced electric current in said primarywinding for producing a voltage in said secondary winding fordistribution to said spark plugs and for periodically sequentiallyclosing the circuit of said primary winding substantially at theattainment of maximum flux in said core during operation of said system,and means for sequentially closing the circuit of said tertiary windinga short interval after each opening or said primary winding circuitbreaker and after electrical breakdown of said spark plugs fordissipating the electromagnetic energy of said magneto in said tertiarywinding, said latter means also being operable for sequentially openingthe circuit of said tertiary winding a short interval before eachclosing of said primary winding circuit breaker.

9. An ignition system including a magneto having a magnetic circuit witha core of magnetic material, a primary winding on said core, a secondarywinding on said core, a tertiary winding on said core, a plurality orspark plugs, a'dis- 'tributor arranged to distribute ignition currentsequentially to said spark p gs Irom said secondary winding, means forsequentially opening the circuit of said primary winding n attainment ofsubstantially maximum induced electric current in said primary windingfor producing a voltage in said secondary winding for distributlon tosaid spark plugs and for periodically sequentially closing the circuitof said primary winding substantially at the attainment of maximum fluxin said core during operation of said system, and means including atertiary winding circuit breaker operable for sequentially closing thecircuit of said tertiary winding a short interval after each openingofsaid primary winding circuit breaker and aiter electrical breakdown ofsaid spark plugs for dissipating the electromagnetic energy of saidmagneto in said tertiary windin said tertiary winding circuit breakermeans also being operable I'or sequentially opening the circuit of saidtertiary winding a short interval before each closing of said primarywinding circuit breaker.

10. An ignition system including a magneto having a magnetic circuitwith a core of magnetic material, a primary winding on said core, asecondary winding on said core, a tertiary winding on said core, aplurality Of spark plugs, a aistricutor arranged to distribute ignitioncurrent sequentially to said spark plugs mom said secondary winding,means including a primary winding circuit breaker operable I01sequentially opening tile circuit 01 said primary winding 0n attainmentor suostantlally'maxilllum induced electric current in said primarywlnumg ror proauclng a voltage m sald secondary winding lor distributionto said spark plugs and mr periodically sequentially closing the worm orsaid primary winding suostantlally at the attainment or maximum lluk insaid cure uullug operatlon of said system, and means lor sequentiallyclosing we circuit or said tertiary winning a snort interval alter eacnopening or said primary winding circult breaker and aiter electricalbreakdown of said spark plugs Ior dissipating electromagnetic energy orsaid magneto in said tertiary wmumu. said latter means also beingoperable lor sequentially opening the circuit or said tertiary winding ashort interval before each closing of said primary winding circuitbreaker.

11. An ignition system including a magneto,

having a magnetic circuit with a core of magnetic material, a primarywinding on said core, a secondary winding on said core, a tertiarywinding on said core, a plurality of spark plugs, a distributor arrangedto distribute ignition current sequentially to said spark plugs fromsaid 'secondary winding, means including a primary winding circuitbreaker operable for sequentially open- I ing the circuit of saidprimary winding on attainment of substantially maximum induced electriccurrent in said primary winding for producing a voltage in saidsecondary winding for winding, said tertiary winding circuit breakermeans also being operable for sequentially opening the circuit of saidtertiary windinga short interval before each closing of said primarywinding circuit breaker.

WIILIAM I. HNLOR.

